Christopher R Stook

7155071, Dec 26, 2006

Mar 8, 2005

11/074532

Christopher R. Stook - Grant FL, US
Jerry Busby Wood - Melbourne FL, US

Harris Corporation - Melbourne FL

G02F 1/035
H04B 10/04
H04B 10/12

385 2, 398183, 398198, 359239, 359245

An electro-optical device includes an amplifier having an input receiving a data signal, a crossing adjustment input, and an output. The device includes a light source and a Mach-Zehnder modulator having a first input coupled to the output of the amplifier, an optical input coupled to the laser, a bias input, and an optical output. A bias circuit is coupled to the bias input of the Mach-Zehnder modulator and preferably includes a pilot signal generator connected to the crossing adjustment input of the amplifier, and a feedback circuit coupled between the optical output and bias input of the Mach-Zehnder modulator and coupled to the pilot signal generator. The bias circuit applies the pilot signal to the crossing adjust input of the amplifier which forces the modulator to the correct bias point for duobinary transmission. Modulation on +1 and −1 levels is eliminated, and only the 0 level is modulated. The feedback loop forces modulated portion of the waveform to null bias.

6519374, Feb 11, 2003

Mar 30, 1999

09/281235

Christopher Robert Stook - North Wales PA
Stephen Bradley Krasulick - Fogelsville PA

Uniphase Corporation - San Jose CA

G02F 1035

385 2, 385 1, 385 14, 385 24, 385122, 359161, 359180, 359181

A predistortion arrangement is described for using an input signal to drive a nonlinear device having a drive input. Initially, first means sample a portion of the input signal. The sampled portion of the input signal is introduced to at least one predistortion path including a mixer responsive to the sampled portion of the input signal for producing at least second order intermodulation products of the input signal. The second order intermodulation products are conditioned. Combining means then combine the conditioned second order intermodulation products with the sampled input signal in a way which produces a predistorted drive signal compensated for second order distortion for use in driving the drive input of the nonlinear device. In one aspect, the sampling means and the combining means may be provided using resistive networks. The use of the resistive networks eliminates the need for directional couplers incorporating magnetic components.